Daniella, There are power outlets at the bathrooms, as well as outlets by the classroom building. Trails are reasonably accessable, but they are subject to seasonal changes. I would suggest contacting the Rangers to see what the trail conditions are before you go.
There are electric outlets near the sinks.
I recommend getting a power inverter that plugs into a cigarette port in your car. You then have an outlet to power the air pump. You can find these in the automotive area of any Walmart. A home extension cord will let you reach out of your car to the tent. Keep the engine running while you are using the electricity.
I believe that there are power outlets. As for trails, I'm not really sure how safe that are for people who have difficulties with their balance but I'm sure that the nature there is great and it can be very relaxing and enjoyable. As someone mentioned, I would call park rangers before you go, to check the condition of the trails.
If most of the trails are too rocky, you could take one of the access roads. Most of them are closed off to cars and more wide/flat than the trails.
The trails are pretty Rocky and tend to hold a lot of water meaning it can be pretty slick at some points, I have run a bunch of the trails and there aren't really any super flat routes I have gone on. Couldn't answer the outlet question as I haven't camped out there.
Some trails are easier -couple very steep & can be slippery. Nice facilities but not recall outlets.
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